The present invention is directed to an improved film feed apparatus for use in a motion picture projector and particularly to a forward-reverse film transport synchronizing mechanism for a motion picture projector film feed apparatus.
Film feed mechanisms for use in motion picture projectors are well known in the art. Conventional mechanisms of this type may comprise a shuttle arranged for "up and down" or vertical reciprocation. The shuttle is also arranged for "in and out" reciprocation so that a tooth or teeth carried thereby will disengage a film strip at the end of each advancing stroke and engage with perforations in the film strip just prior to and during an indexing stroke. The shuttle is driven for vertical reciprocating motion by a transport cam against which the shuttle is disposed.
Such mechanism additionally includes a rotary shutter having a plurality of radially extending shutter blades, a given one of which covers the projector aperture during both forward and reverse projection. With many mechanisms of prior art, it has been necessary to reverse the direction of angular rotation of a shaft which is coupled to the transport cam and shutter to provide for properly synchronized forward and reverse film transportion. In other words, the direction of rotation of the rotating shaft is reversed so that the shuttle is caused to engage with the film during downward movement for forward projection as opposed to upward movement for reverse projection. When reversing the direction of film transporation, the same shutter blade covers the projection aperture. Because complicated gear arrangements are necessary for changing the angular direction of the rotating shaft, these systems are expensive.
It is therefore an object of the present invention to provide a new and improved motion picture projector film feed apparatus.
It is another object of the present invention to provide an improved forward-reverse film transport synchronizing mechanism for a motion picture projector film feed apparatus.
It is a more particular object of the present invention to provide a forward-reverse film transport synchronizing mechanism which is less complicated than those of the prior art in affording properly synchronized forward and reverse film transportation.